Incremental Cross-Platform Transportable Tablespaces

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Does delphix support Incremental Cross-Platform Transportable Tablespaces to minimize the downtime during migration ?
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HJ

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Posted 1 year ago

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Tim Gorman, Field Services

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HJ,

Delphix does utilize transportable tablespaces during cross-platform migration for the implementation of our Cross-Platform Provisioning (XPP) or UNIX-to-Linux (U2L) capability, as documented by Oracle.

Please be aware that two factors have the most impact on the duration of XPP which are restrictions imposed by Oracle...

  1. Number of database objects in the data dictionary
  2. Volume and number of datafiles

A very large number of database objects in the data dictionary (i.e. >100,000) can result in long duration for the EXPDP TRANSPORT_TABLESPACES and IMPDP TRANSPORT_TABLESPACES commands, because they are single-threaded processes.

Since every single byte of the datafiles must pass through the Oracle RMAN CONVERT DATAFILE command to perform the endian conversion, then obviously the volume (and in some cases the number) of the datafiles in the database can result in long duration.  Delphix is able to scale this operation by using RMAN channels in parallel, and by performing this operation entirely on the target Linux database server, but still any database over 20 TB in size is a going to take a while to convert.

So, if performing SELECT COUNT(*) FROM DBA_OBJECTS returns much more than 100,000, or if SELECT (SUM(BYTES)/(1048576*1048576)) tb FROM DBA_DATA_FILES returns much more than 20 TB, then the duration of the Delphix XPP will be lengthy.

There are a myriad of additional mishaps that can impact the duration or feasibility of XPP, some documented at Oracle and many discovered through experience at Delphix, and we have validation routines to uncover all of these, but these two factors figure prominently.  Please ask Delphix professional services for information on XPP and U2L validation?

Hope this helps?

Thanks!
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HJ

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Thanks, !